Multi-purpose switch activated system and method for using same

ABSTRACT

According to one embodiment, a system with a multi-purpose switch for providing a power on function and other functions to a user comprises a temporary power control circuit configured to be coupled to and decoupled from a power source by the multi-purpose switch. The system also comprises a continuous power control circuit to provide continuous power. As a result, the multi-purpose switch is capable of providing other functions when the continuous power is being provided. In one embodiment, a method for utilizing a multi-purpose switch to provide a power on function and other functions to a user comprises coupling a temporary power control circuit to a power source by the multi-purpose switch, triggering a continuous power control circuit to provide continuous power, decoupling the temporary power control circuit from the power source by the multi-purpose switch, and making the multi-purpose switch available to provide other functions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally in the field of electronics. Morespecifically, the present invention is in the field of electroniccircuits and systems.

2. Background Art

Advances in fabrication technology are enabling production of electronicsystems that are ever more portable and of progressively diminishedsize. As their portability has increased, these systems have comeincreasingly to rely on modular power sources, such as batteries, toprovide them with operating power. Moreover, as system size hasdiminished, the batteries relied upon for power have become smaller aswell. Despite advances in energy storage efficiency, the reduction inbattery size mandated by smaller electronic system architectures hasresulted in reduction of the total stored energy available to powerthose systems. An undesirable consequence of these otherwiseadvantageous improvements in dimensional reduction is that electronicsystems utilizing integrated circuits produced by means of sub-micronand deep sub-micron fabrication technologies are now challenged bylimited battery life due in part to current leakage within thosesystems.

An additional challenge posed by reduced device and system size resultsfrom the effect of dimensional restriction on user controls. Inevitably,as the size of a system or device is reduced, the area available toaccommodate user input controls is reduced as well. Consequently, theuser of a modern diminutive electronic system may be severely limited inthe number and variety of system commands under his or her control, dueto a limitation on the number of separate input controls that can besupported by the system architecture.

One conventional approach to improving battery life in a batteryoperated electronic system addresses leakage in the circuit enablingpower to the system. For example, more than one power mode may be madeavailable to limit sources of leakage from inactive circuits within thesystem. By way of a specific example, an electronic system comprising aBluetooth headset may be configured to have three such power modes, off,standby, and fully activated, where the standby mode preserves batterylife while maintaining system responsiveness to communication signals.This conventional approach, although offering some advantages withrespect to preserving battery life, fails to resolve, or even address,disadvantages associated with the limited number of user input controlson those and smaller electronic systems.

Thus, there is a need in the art for a solution enhancing the efficiencyof an electronic system by increasing the functionality of a user inputcontrol, while enabling power conservation.

SUMMARY OF THE INVENTION

A multi-purpose switch activated system and method for using same,substantially as shown in and/or described in connection with at leastone of the figures, and as set forth more completely in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a conventional implementation for providingpower to an electronic system.

FIG. 2 is a block diagram of a multi-purpose switch activated system,according to one embodiment of the present invention.

FIG. 3 shows exemplary control signals used by the multi-purpose switchactivated system of FIG. 2 in the time domain, according to oneembodiment of the present invention.

FIG. 4 is a flowchart of a method for utilizing a multi-purpose switchactivated system, according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to a multi-purpose switch activatedsystem and method for using same. Although the invention is describedwith respect to specific embodiments, the principles of the invention,as defined by the claims appended herein, can obviously be appliedbeyond the specifically described embodiments of the invention describedherein. Moreover, in the description of the present invention, certaindetails have been left out in order to not obscure the inventive aspectsof the invention. The details left out are within the knowledge of aperson of ordinary skill in the art.

The drawings in the present application and their accompanying detaileddescription are directed to merely exemplary embodiments of theinvention. To maintain brevity, other embodiments of the invention,which use the principles of the present invention are not specificallydescribed in the present application and are not specificallyillustrated by the present drawings.

FIG. 1 is a block diagram of a conventional implementation for providingpower to an electronic system. FIG. 1 shows system 100 in combinationwith a power source such as battery 102. Power from battery 102 may beprovided to system 100 through line 104 and switch 106. Switch 106 maybe engaged or disengaged to, respectively, couple or decouple system 100from battery 102. Also shown in FIG. 1 are power management unit (PMU)110, PMU input 112, and PMU output 114. Additional system elementsinternal to system 100 receiving PMU output 114 are not shown in FIG. 1for purposes of clarity and brevity. System 100 may be implemented on asingle semiconductor die and be utilized in a portable radio frequency(RF) communication device, for example.

In a conventional approach to providing power to an electronic systemsuch as that shown in FIG. 1, switch 106 may be used to control thedeliver of power to system 100, thereby providing a mechanism forlimiting depletion of battery 102. In one conventional implementation,for example, switch 106 may provide a user with two power options ormodes, on and off, permitting the user to fully activate system 100, orfully deactivate the system by, respectively, coupling or decoupling PMU110 from battery 102. In another conventional implementation, switch 106may provide a user with three power modes. In that implementation, forexample, system 100 could be placed into a standby mode, in addition tobeing fully activated in an on state, or fully deactivated in an offstate.

In the second described conventional implementation providing threepower modes, standby mode may correspond to partial coupling of battery102 to system 100 by switch 106. For example, in standby mode, switch106 may provide PMU input 112, but not enable full activation of system100. In that implementation, when set to the intermediate standby mode,switch 106 might partially couple system 100 to battery 102, so that PMU110 might receive PMU input 112, but would not deliver PMU output 114 tofully power up system 100. As a result, standby mode could be used toplace system 100 in an operative condition, for example, make itresponsive to RF communication signals, while not fully activatingsystem functionality and thereby conserving battery 102.

As shown in FIG. 1, power switch 106 may be used to control delivery ofpower to system 100, and, as a result, be used to limit depletion ofbattery 102 through leakage resulting from unnecessary coupling ofunneeded circuits within system 100. Whether or not the conventionalimplementation provides an effective approach to limiting power leakagein a battery operated system, the function of switch 106 in such asystem is dedicated exclusively to providing power. In other words, inFIG. 1, switch 106 is a power switch used solely to power system 100 onand off. As explained previously, however, system 100 may be implementedin a user device having a very small device architecture, so that spaceavailable for user control inputs may be at a premium. As a result, theconventional implementation shown in FIG. 1, while providing options forreducing leakage current and conserving battery life, disadvantageouslydedicates switch 106 to a single power on function.

FIG. 2 is a block diagram of a multi-purpose switch activated system,according to one embodiment of the present invention, capable ofovercoming the drawbacks associated with the conventional implementationdescribed previously in relation to FIG. 1. FIG. 2 shows diagram 200,which displays system 200 in combination with battery 202 correspondingto battery 102 in FIG. 1. Also shown in FIG. 2 are power management unit(PMU) 210, PMU output 214, and PMU inputs 212 a and 212 b. As in FIG. 1,additional system elements powered by PMU output 214 and not shown inthe present drawings for purposes of clarity and brevity.

In the embodiment of FIG. 2, multi-purpose switch 206 is shown as a pushbutton switch. In other embodiments, however, multi-purpose switch 206may be a slide switch, or toggle switch, for example. As shown in FIG.2, system 200 also comprises input buffer 216, temporary power controlcircuit 220, and continuous power control circuit 230. According to thepresent embodiment, temporary power control circuit 220 includes diode222, capacitor 224, and drawdown resistor 226, coupled to node 228.Moreover, in the present embodiment, continuous power control circuit230 includes power on register 232, output buffer 234 and resistor 236.

System 200 may be implemented on a single semiconductor die, and may beused in a communication system in, for example, a wirelesscommunications device, a mobile telephone, a Bluetooth enabled device, acomputer, a personal digital assistant (PDA), a digital media player, agaming console, or in any other kind of system, device, component, ormodule responsive to user input controls utilized in modern electronicsapplications. In one embodiment, system 200 may be, or may reside in, aprocessor chip, for example.

System 200 includes multi-purpose switch 206 for providing a power onfunction and other functions to a user. In a first activation ofmulti-purpose switch 206, temporary power control circuit 220 can becoupled to battery 202 by multi-purpose switch 206, to provide temporarypower to PMU 210, allowing power up of system 200. Subsequently,continuous power control circuit 230 can be triggered to providecontinuous power to PMU 210, supporting continued operation of system200. Multi-purpose switch 206 is capable of then providing otherfunctions to a user of system 200, once continuous power to PMU 210 isestablished.

Engagement of multi-purpose switch 206 in a first activation maycorrespond to a user action depressing a push button switch. That actioncauses current to flow along line 204 b through multi-purpose switch206, from battery 202 to node 228. Although in the present embodiment,the power source for system 200 is battery 202, in other embodimentsvarious suitable power sources, not limited to a battery, might beemployed. Current flowing into node 228 causes a voltage to accumulateacross capacitor 224. Continued engagement of multi-purpose switch 206,for example as a result of continuous depression of a push button switchby a user of system 200, leads to a continued increase of voltage acrosscapacitor 224. When, due to the voltage on capacitor 224, an appropriatediode threshold voltage is achieved at node 228, diode 222 will beforward biased and will provide a power on signal in the form oftemporary power at PMU input 212 b. The present embodiment shows node222 coupled to a single capacitor. In other embodiments, however,capacitor 224 can be replaced by a network of capacitors comprising morethan one capacitor.

In response to the temporary power received from diode 222 at PMU input212 b, PMU 210 enables power up of system 200 by drawing power frombattery 202 through line 204 a. Operational power is received by PMU 210as PMU input 212 a, whereupon PMU output 214 is provided to theremainder of system 200. Accumulated voltage present at node 222 isfurther reflected by the output of input buffer 216. In effect, inputbuffer 216 provides an on signal as an output when multi-purpose switch206 is engaged, and an off signal as an output when multi-purpose switch206 is disengaged. According to the present embodiment, system 200 isconfigured such that a first activation of multi-purpose switch 206 in apower on function results in the on signal output of input buffer 216being entered in power on register 232 of continuous power controlcircuit 230. In other embodiments, a first activation of multi-purposeswitch may be stored by other means. For example, system 200 may includefirmware that reads a random access memory (RAM) record formed inresponse to a first on signal provided as an output by input buffer 216.

In the embodiment of FIG. 2, an entry in power on register 232corresponding to a first on signal provided by input buffer 216,triggers output buffer 234 to provide a power on signal as continuouspower through resistor 236, at PMU input 212 b. Triggering of outputbuffer 234 and the resultant provision of continuous power to PMU 210may be indicated to a user of system 200 by means of a visual or audiosignal, such as an illuminated light or audible beep, for example,whereupon multi-purpose switch 206 may be disengaged in a firstdeactivation. The described first deactivation of multi-purpose switch206 results in temporary power control circuit 220 being decoupled frombattery 202.

Despite decoupling of temporary power control circuit 220 from battery202, PMU 210 continues to be enabled due to input at PMU input 212 b ofa power on signal as continuous power provided by continuous powercontrol circuit 230. Decoupling of temporary power control circuit 220from battery 202 results in termination of current flow into node 228from battery 202. Voltage accumulated at node 222 due to capacitor 224is dissipated through drawdown resistor 226, resulting in an off signalbeing provided as an output of input buffer 216. It is noted thatalthough in the present embodiment drawdown resistance is provided bydrawdown resistor 226, in another embodiment, drawdown resistance may beprovided by a resistive network comprising more than one drawdownresistor.

As a result of voltage drawdown through drawdown resistor 226, node 228goes from a voltage high, associated with the charging of capacitor 224,to a voltage low, associated with discharge of capacitor 224. Thevoltage at node 228 is further reflected by the output of input buffer216, which provides an off signal. Consequently, the output of inputbuffer 216 becomes an indicator of the present activation state ofmulti-purpose switch 206, that is, activation of multi-purpose switch206 results in accumulation of voltage at node 228 due to capacitor 224,and an on signal as the output of input buffer 216, while deactivationof multi-purpose switch 206 results in a voltage drop at node 228 due todrawdown resistor 226, and on off signal as the output of input buffer216.

Because continuous power is being provided to PMU 210 by continuouspower control circuit 230, subsequent activations of multi-purposeswitch 206 can be used to provide functions other than power on. Forexample, in a handheld communication device, multi-purpose switch 206could be utilized in a first activation to power the device on, in asecond activation to adjust volume, in a third activation to scroll to adesired display screen in conjunction with highlighted commandsappearing on a user interface (not shown in FIG. 2).

Turning now to FIG. 3, FIG. 3 shows exemplary control signals used bysystem 200 in FIG. 2, in the time domain, according to one embodiment ofthe present invention. Graph 300, in FIG. 3 includes trace 306corresponding to the present activation state of multi-purpose switch206, in FIG. 2, which is similarly reflected by the output of inputbuffer 216. Also shown on graph 300 is trace 328, corresponding to thevoltage appearing at node 228, in FIG. 2. Trace 314 on graph 300corresponds to power delivered to system 200, in FIG. 2, as PMU output214, while trace 332 on graph 300 corresponds to the entry held by poweron register 232, serving as the trigger for continuous power controlcircuit 230, in FIG. 2. It is noted that graph 300 is provided as aconceptual aid, and is not intended to precisely reflect the behavior ofthe elements of system 200. In particular, as is well known, the timerate-of-change of voltage accumulated on a capacitor during charging isa nonlinear phenomenon, and trace 328 on graph 300 is not intended tosuggest otherwise with respect to the embodiment of FIG. 2.

Trace 306, on graph 300, shows that multi-purpose switch 206 is ininitially not activated. For the example of a push button switch, 1^(st)Activation corresponds to depressing the push button switch to perform apower on function. Trace 306 shows that the exemplary push button switchwould remain continuously depressed for a period of time, for exampleapproximately one second, and then be released in response to a userfeedback signal indicating power up of system 200. This is further shownby traces 328, 314, and 332.

Trace 328 shows the voltage state of node 228, in FIG. 2. As shown bygraph 300 and system 200, the initial voltage at node 228 is low due tothe effect of drawdown resistor 226, which is coupled to ground.Beginning with a 1^(st) Activation, coinciding with depression of thepush button switch by a user, the voltage at node 228 increases due tovoltage accumulation by capacitor 224. When the voltage at node 228reaches a threshold voltage for diode 222, which may be, for example,approximately 0.7 V, diode 222 is forward biased by capacitor 224.Continuous depression of the push button switch causes the voltage atnode 228 to remain high. At a 1^(st) Deactivation, or release of thepush button switch by a user, the voltage at node 228 drops to a lowvalue due to the action of drawdown resistor 226 in the absence ofcoupling to battery 202, returning to a low value after a time intervallasting from approximately several microseconds to a few milliseconds,for example.

As shown by trace 314, after a brief delay, perhaps also lasting fromapproximately several microseconds to a few milliseconds, for example,and shown by interval 310, PMU 210, in FIG. 2, provides PMU output 214,and powers up system 200. As explained in conjunction with FIG. 2,according to the present embodiment, power up of system 200 includesmaking an entry in power on register 232 corresponding to the output ofinput buffer 216. Input buffer 216 reflects the present activation stateof the push button switch, so that during the power up interval,initiated by temporary power provided by temporary power control circuit220, the output of input buffer 216 will provide an on signal. Entry ofthe on signal into power on register 232 during the power up intervalresults in triggering of output buffer 234, resulting in delivery ofcontinuous power by continuous power control circuit 230.

Transition from provision of temporary power to provision of continuouspower is further shown in graph 300 by the region to the right of the1^(st) Deactivation. In that region, the push button switch has beenreleased by the user, resulting in decoupling of temporary power controlcircuit 220 from battery 202, and subsequent drawdown of the voltageaccumulated at node 228. Despite absence of temporary power provided toPMU 210, however, PMU output 214 and system power remain on, as a resultof continuous power provided by continuous power control circuit 230,activated by the presence of a power on entry in power on register 232.

The operation of system 200 in FIG. 2 is further explained incombination with FIG. 4, which shows flowchart 400 describing the steps,according to one embodiment of the present invention, for utilizing amulti-purpose switch activated system. Certain details and features havebeen left out of flowchart 400 that are apparent to a person of ordinaryskill in the art. For example, a step may comprise one or more substepsor may involve specialized equipment or materials, as known in the art.While steps 410 through 450 indicated in flowchart 400 are sufficient todescribe one embodiment of the present invention, other embodiments ofthe invention may utilize steps different from those shown in flowchart400.

Referring to step 410 of flowchart 400, in conjunction with FIG. 2 andFIG. 3, step 410 comprises coupling temporary power control circuit 220to battery 202 by a first activation of multi-purpose switch 206.Coupling temporary power control circuit 220 to battery 202 providestemporary power to PMU 210 of system 200, as described in relation toFIG. 2. As earlier noted, in another embodiment, battery 202 cancorrespond to any suitable power source for an electronic system.Moreover, multi-purpose switch 206 may comprise a push button switch, asshown in FIG. 2, but may also comprise other switch mechanisms, such asa slide switch, or toggle switch, for example. As was previouslydescribed, coupling of temporary power control circuit 220 to battery202 provides a power on signal as temporary power to PMU 210. As aresult, in step 420 of flowchart 400, PMU 210 is enabled and providesPMU output 214 to power entire system 200.

Continuing with step 430 of flowchart 400, step 430 comprises triggeringcontinuous power control circuit 230 to provide continuous power to PMU210. As explained during the description of FIG. 2, continuous powercontrol circuit 230 can be triggered in response to making an entry inpower on register 232 corresponding to the on signal provided by inputbuffer 216. In another embodiment, information corresponding to the onsignal provided by input buffer 216 may be written to a memory cell by afirmware controlling power up of system 200, for example, and thatmemory cell may be accessed to trigger continuous power control circuit230.

Proceeding with step 440 of flowchart 400, step 440 comprises decouplingtemporary power control circuit 220 from batter 202 by a firstdeactivation of multi-purpose switch 206. As discussed, triggering ofcontinuous power control circuit 230, in step 430, makes it possible toterminate provision of temporary power from temporary power controlcircuit 220, without effecting the power on state of system 200. Ineffect, continuous power control circuit 230 replaces temporary powercontrol circuit 220 as the source of a power on signal to PMU 210. As aresult, PMU input 212 is supplied by elements internal to system 200,rather than being drawn from battery 202. Consequently, decoupling oftemporary power control circuit 220 from battery 202 reduces leakagefrom battery 202, thereby conserving battery power.

In step 450 of flowchart 400, multi-purpose switch 206 may be madeavailable to a user of system 200 for functions other than power on, asdescribed in conjunction with FIG. 2. It is noted that one of the otherfunctions made available to a user of system 200 may be a power offfunction. Thus, in one embodiment, multi-purpose switch 206 may be usedinitially for power on, subsequently for functions such as scrolling, orvolume control, for example, before being used to power off system 200.Those additional functions can be executed by subsequent respectiveactivations of multi-purpose switch 206, following the first activationas a power on function. In one embodiment, a user need not affirmativelypower off system 200. In that embodiment, system 200 is furtherconfigured to shut down continuous power control circuit 230 after apredetermined time period of nonuse of system 200.

By utilizing a multi-purpose switch to couple a temporary power controlcircuit to a power source in order to deliver temporary power to anelectronic system while also causing a continuous power control circuitto be triggered, the present disclosure describes a novel implementationfor activating the system. By subsequently decoupling the temporarypower control circuit from the power source, the present disclosureenables the twofold advantages of reduced power leakage and availabilityof a multi-purpose switch for other functions in addition to powering onthe system. As a result, the present application discloses embodimentswhich prolong battery life when external power is supplied by a batterysource. Moreover, the present application reveals a system and methodwhich further improve the efficiency of an electronic system byproviding enhanced functionality of a user input control in the form ofa multi-purpose switch.

From the above description of the invention it is manifest that varioustechniques can be used for implementing the concepts of the presentinvention without departing from its scope. Moreover, while theinvention has been described with specific reference to certainembodiments, a person of ordinary skill in the art would recognize thatchanges can be made in form and detail without departing from the spiritand the scope of the invention. The described embodiments are to beconsidered in all respects as illustrative and not restrictive. Itshould also be understood that the invention is not limited to theparticular embodiments described herein, but is capable of manyrearrangements, modifications, and substitutions without departing fromthe scope of the invention.

Thus, a multi-purpose switch activated system and method for using samehave been described.

1. A system with a multi-purpose switch for providing a power on function and other functions to a user, said system comprising: a temporary power control circuit being configured to be coupled to and decoupled from a power source by said multi-purpose switch to provide temporary power to a power management unit; a continuous power control circuit to provide continuous power to said power management unit; said multi-purpose switch being capable of providing said other functions when said continuous power is provided to said power management unit; wherein said system is implemented using a single semiconductor die.
 2. The system of claim 1, wherein said power source comprises a battery.
 3. The system of claim 1, wherein said multi-purpose switch comprises a push button switch.
 4. The system of claim 1, wherein said temporary power control circuit comprises a diode delivering said temporary power to said power management unit, said diode being coupled to and forward biased by one or more capacitors.
 5. The system of claim 4, wherein said temporary power control circuit further comprises one or more drawdown resistors.
 6. The system of claim 1 further comprising an input buffer coupled to said multi-purpose switch, said input buffer being configured to provide an on signal when said multi-purpose switch is engaged and an off signal when said multi-purpose switch is disengaged.
 7. The system of claim 1, wherein said continuous power control circuit comprises a power on register coupled to an output buffer providing said continuous power to said power management unit.
 8. The system of claim 7, wherein said output buffer is triggered by an entry in said power on register corresponding to a first on signal.
 9. The system of claim 1, wherein said continuous power control circuit ceases providing said continuous power to said power management unit after a predetermined time period of system nonuse.
 10. The system of claim 1 utilized as a part of a communication system, said communication system being selected from the group consisting of a wireless communications device, a mobile telephone, a Bluetooth enabled device, a computer, a personal digital assistant (PDA), a digital media player, and a gaming console.
 11. A method for utilizing a multi-purpose switch in an electronic system to provide a power on function and one or more other functions to a user of said electronic system, said method comprising: implementing a temporary power control circuit, a continuous power control circuit, and said multi-purpose switch, using a single semiconductor die; coupling said temporary power control circuit to a power source by a first activation of said multi-purpose switch to provide temporary power to a power management unit of said electronic system; triggering said continuous power control circuit to provide continuous power to said power management unit; decoupling said temporary power control circuit from said power source by a first deactivation of said multipurpose switch; making said multi-purpose switch available to provide said one or more other functions to said user.
 12. The method of claim 11, further comprising enabling said power management unit to provide power to said electronic system.
 13. The method of claim 11, further comprising executing said one or more other functions in response to subsequent activations of mid multi-purpose switch.
 14. The method of claim 11, further comprising shutting down said continuous power control circuit after a predetermined time period of nonuse of said electronic system.
 15. The method of claim 11, wherein mid first activation of said multi-purpose switch comprises engaging a push button switch.
 16. The method of claim 11, wherein mid electronic system comprises a battery operated electronic system.
 17. The method of claim 11, wherein mid temporary power control circuit comprises a diode delivering mid temporary power to said power management unit, said diode being coupled to and forward biased by one or more capacitors.
 18. The method of claim 17, wherein said temporary power circuit further comprises one or more drawdown resistors.
 19. The method of claim 11, wherein said continuous power control circuit comprises a power on register coupled to an output buffer providing said continuous power to said power management unit.
 20. The method of claim 19, wherein said output buffer is triggered by an entry in said power on register corresponding to said first activation of said multi-purpose switch. 